bump PMD version to 6.1.0

See merge request !6

build versioning

See merge request !4

- specify `dacapo.version` and `dacapo.nickname` in dacapo.properties file;
- build versino is dacapo version + git hash; this can be overwritten by cmd args;
- use `build.target-jar` as output jar name; append build version to jar name.

Version bump eclipse

See merge request !2

[eclipse] Updated the version of eclipse since the newer version fix the bug that eclipse doesn't work with openjdk8 properly